Apparatus for feeding pulverized fuel to a plurality of fire-boxes.



No. 684,!52. Patented Dot. 8, I901. w. m. WHEILDON.

APPARATUS FOR FEEDING PULVERIZED FUEL TO A PLURALITY OF FIRE BOXES.(Application filed Aug. 2; 1900.)

(No Model.) 2 Sheets-Sheet l.

Q Q a M Witnesses Inven t or Tm. norms Ps'rsas an. PHOYO-LITHQ. wnsnmommu. c.

Patented Oct. 8, [90L w. u. WHEILDON. APPARATUS FOR FEEDING PULVEBIZEDFUEL TO A PLUBALITY OF FIRE BOXES.

(Application filed Aug. 2, 1900.

2 SheetsSheat 2.

(No Model.)

Inventor Witnesses M Attys.

Tn: mums vzrzns cu, Pmouwov, WASHINGTON. n, c.

UNITED STATES PATENT OFFICE.

XVILLIAM MAXWELL WVHEILDON, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THEAERO-PULVERIZER COMPANY, OF JERSEY CITY, NEAV JERSEY.

APPARATUS FOR FEEDING PULVER-IZED FUEL T vA .PLURALITY .OF FIRE-BOXES.

SPECIFICATION forming part of Letters Patent No. 684,152, dated October8, 1901.

Application filed August 2. 1900. Serial No. 25,655. (No model.)

To all whom it may concern.-

Be it known that I, WILLIAM MAXWELL \VHEILD'ON, a citizen of the UnitedStates, residing at Boston, in the county of Suifolk and State ofMassachusetts, have invented a 'cer tain new and useful Apparatus forFeeding Pulverized Fuel to a Plurality of Fire-Boxes, (Case-A,) of whichthe following is a specification.

My invention relates to an improved apparatus by means of whichpulverized fuel can be practically and economically fed from one or morepulverizers to a pluralityof fire-boxes, burners,orotherfuel-consumingdevices;and

the object of my invention is to provide a simple and. effectiveapparatus for the purpose wherein the desired proper distribution 'ofthe fuel will be secured and wherein one or more of the fuel-consumingdevices can be connected to or disconnected from the supply ofpulverized fuel without affecting to an objectionable extent the propersupply of fuel to the other fuel-consuming device or devices of thesystem. Pulverizers of many types have been suggested for reducing coalor other fuel into finely-comminuted condition and mixing the powderedproduct with air, and my present invention is not limited to use with apulverizer of any specific type. A con- 0 venient form of pulverizingdevice, however,

and one which 1 preferably use is that suggested in the patent toStorer, Martin, and Eaton, No. 580,909, dated April 20, 1897, cmployinga series of concentric pulverizing- 5 chambers of grad ually-increasingdiameter from the feed to the discharge end, a fan-chamber beingconnected to the pulverizing-chamber of the largest diameter and a shaftbeing 7 mounted centrally in the pulverizing and fan 0 chambers andcarrying a series of paddles working in the pulverizing-chambers and aseries of fan-blades working in the fan-chamber, a suitable feedingdevice being ordinarily employed to secure a uniform feed of materialaround the shaft and within the first pulverizing-chamber. Theemployment of a single pulverizer or of aplurality of pulverizers forfeeding a mixture of air and pulverized fuel to a plurality offuel-consuming'deviceshas been before suggested, but so far as I amaware with the prior devices a plurality of feed-pipes have led directlyfrom the discharge end of the pulverizer to the fuel-consuming devices,so that variations in the feed of fuel to one resulted in correspondingvariations in the feed of the fuel to the other. \Vith such a device ifit were assumed, for example, that the pulverizer was used to feedpulverized fuel through two branch pipes to two fuel-consuming devicesthe shut-off of one device would result in the doubling of the supply offuel to the other. For this reason it has been practically impossible upto the present time to satisfactorily feed pulverized fuel from a singlepulverizer to a plurality of fuel-consuming devices. By means of mypresent apparatus Isecure this desired result.

In carrying my invention into effect I employ a trunk or fuel-pipe whichleads from the discharge end of a pulverizer or a series of pul- 7o'verizers and extends more or less adjacent to allof the fuel-consumingdevices which are to be supplied with the pulverized fuel, said trunk orfuel-pipe returning to the pulverizer at the inletsideofthefan-ehamberthereof and preferably between the fan-chamber and thepulverizing chamber or chambers, andIlead a branch from the trunk orfuel-pipe into each fuel-consuming device,whereby fuel from the trunk orfuel-pipe will be permitted to enter the branch pipe and be directedWith the desired pressure into each fuel-consuming device. \Vhen thepulverizer is not provided with a fan-chamber, but material is caused topass therethrough and to be mixed with air by an independent fan, thenthe trunk or fuelpipe may be returned to such a fan-chamber instead ofto the pulverizer itself. In this Way I am enabled to produce a constantcirculation of air and pulverized fuel from the exit 0 ends of thepulverizer or from the fan-chamber if an independent fan be used and toreturn to such pulverizer or independent fanchamber the surplus air orpulverized fuel not drawn ofi into the fuel-consuming devices, 5 wherebya very high velocity of air and fuel may be maintained in the trunk orfuel-pipe and a uniform feed of material to the several fuel-consumingdevices be secured and any possibility of a back pressure being imposed[00 upon the pulverizer be overcome. It is important that the pulverizershould not work against a back pressure, since in that case the properflow of material to be pulverized through the pulverizer would beaffected. In the preferred embodiment of my invention I make the trunkor fuel-pipe of reduced crosssection beyond each branch leading to theseveral fuel-consuming devices in order to compensate for the normalwithdrawal of material through said devices and to thereby maintain apractically uniform velocity of air in the trunk, and I also preferablyso regulate the normal feed of pulverized material from the pulverizeras to approximately secure the full volume necessary for all thefuel-consuming devices to be fed, so that there will always besufi'icient fuel in transit in the trunk to feed the maximum number ofsuch devices, while any air or fuel returning to the pulverizer or itsdraft-producing device will be of minimum quantity. If then one or moreof the fuel-consuming devices be disconnect ed from the trunk orfuel-pipe, the quantity of air and fuel returning to the pulverizer willbe increased, so that the conditions can be immediately adjusted bylowering the feed of material introd need to the pulverizer. Thematerial can be drawn off from the trunk or fuel-pipe into the severalfuel-consuming devices in any suitable way, either by means of a smallauxiliary fan at each branch pipe or by the pressure of the air therein,or by both of such expedients.

In my present application. for patent I will describe and claimspecifically the employment of a centrifugal fan at each branch pipe foreffecting the proper feed of material to the several fuel-consumingdevices, and I shall describe and claim in a separate companionapplication filed on even date here-.

with and numbered serially 25,656 the employment of branch pipes, theflow in which is derived solely from the pressure in the trunk; but inits generic aspect my present invention is not limited to any particulardevice for securing the proper feed of the material from the trunk orfuel-pipe to the fuelconsnming devices, and I desire to have my claimsso considered unless specifically lim ited in terms.

In order that my invention may be better understood, attention isdirected to the accompanying drawings, forming a part ofthisspecification, and wherein- Figure 1 is atop. view showing apulverizer of.the type described supplying pulverized fuel to sixfire-boxes of an ordinary kiln and illustrating the employment of anauxiliary centrifugal fan for effecting the feed from the trunk orfuel-pipe into such fire-boxes; Fig. 2, an enlarged view showing one ofthe takeoff casings and fan, and Fig. 3 a section on the line 3 3 ofFig. 2.

In all of the above views corresponding arts are represented by the samenumerals ireference. Y

though I describe my present apparatus in connection with the fire-boxesof akiln, it 7 V will be understood, of course, that it may be appliedin any art wherein a plurality of fuelconsuming devices are employedas,for inif stance, with a battery of boilers, with a series i pulverizerclaimed in the patent to Storer, 7

Martin, and Eaton before referred to, comprising three concentricpulverizing-chambers 4, 5, and 6, a fan-chamber '7, connected to thepulverizing-chamber 6, a main shaft 8, driven by a pulley 9, a suitablefeed device 10 for feeding material to the chamber 4, an exit 11 fromthe fan-chamber, through which the pulverized material and air aredirected,'the paddles 12, carried by spider-arms connected to the shaft8 and working in the several pul- V verizing-chambers, and thefan-blades 13, connected to said shaft and working in the fan-chamber.Material introduced by the feed device 10 into the pulverizing-chamber 4will be gradually reduced-in size by the action of the paddles 12 and befed slowly through the pulverizer, so as to be mixed with air and beforced by the fan through the discharge-opening 11. V i

14 is the main trunk or fuel-pipe, one end of which connects, as shown,with the dis. 100.

charge-opening 11 of the pulverizer,whereby the material from thepulverizer will be forced.

through said trunk. The trunk extends, as

shown, adjacent to all the fire-boxes which l are to be supplied withpulverized fuel. Opposite to each of the twyers 2 I connect the trunkwith a take-01f box 15, which may be conveniently and economically madeof the same size throughout. The trunk 14 is preferably, however,reduced in area beyond each of the takeofi boxes, so as to compensatefor the twyers, whereby the velocity of flow of the material in thetrunk will be maintained practically uniform. leads, as shown, back tothe pulverizer, so that a constant flow of pulverized material and aircan be maintained between the pulverizer and the trunk. When apulverizer of the type described is used, the end 16 of the trunk orfuel-pipe may lead to the pulverizer,-as shown, between the pulverizing-The end 16of the trunk chamber of the greatest diameter and the fan-vchamber, so that any excess of air and fuel will be returned only to thefan-chamber and be again forced out of the pulverizerby the fan.

If the pulverizer used with my apparatus 7 is not of the type employinga fan-chamber mounted concentric to the pulverizing chamher or chambers,then the trunk or fuel-pipe may be returned to an independentfan-chamber, if used, so as to secure the desired circulano r the normalwithdrawal of material to each of. a 7

tion. Connected with the trunk 'or fuel-pipe at each fire-box is abranch pipe 17 through which'fuel may be diverted from the trunk intoany one of the fire-boxes it is desired. When an auxiliary centrifugalfan is employed at each branch to effect the feed there through, aconvenient construction for the purpose is shown in Figs. 2 and 3, towhich attention is now particularly directed.

Bolted to the top of each take-off box is a casting 18, having a flue 19therein,which connects with the interior of the takeoff box, as shown.Said flue is adapted to be closed at its lower end by means of a fiap ordamper 20, pivoted to a shaft 21 and opening upwardly, as shown, so asnot to project within the takeoff box to permit the formation ofeddy-currents therein. The shaft 21 may connect with a regulating-arm 22for adjusting the position of the damper 20. Said arm may be providedwith a slotted segment, with which a locking-screw 24 engages, saidsegment carrying an index 25, which cooperates with the scale 26. Boltedto the vertical face of the casting 18 is a small centrifugal fan 27 ofany desired type, driven from a pulley 28, from an auxiliary engine, orfrom the line-shafting. The flue 19 connects axially with the fan, as iscommon. The discharge-opening 29 of the fan 27 connects with the branch17.

Assuming an auxiliary centrifugal fan to be used at each branch foreffecting the feed from the trunk or fine to the several fuel-consumingdevices, the operation of my improved apparatus will be as follows:Assuming that no one of the fuel-consuming devices is in operation, butthat all require to be started, the pulverizer is actuated to reduce thefuel to a pulverulent condition and to force the pulverized fuel, withthe proper air to create the draft, through the trunk or fuel-pipe 14.All the dampers 20 will be closed, so that a continuous passage will beafiorded through the trunk, and the material and air will return to thefuel-pipe, so as to be maintained in active circulation. As soon as thestream of fuel and air has been thus circulated through the trunk thesupply of fuel to the pulverizer is substantially cut off at the feed10. At the first fire-box the damper 20 is opened to the desired extentand the centrifugal fan 27 is started thereat, so as to draw thematerial and air from the trunk or flue and force such mixture to thetwyer or other burner, which will then be ignited. The supply ofmaterial to said burner will be regulated by the damper 20 or by thespeed of the centrifugal fan, or by both. If it is found that theproportion of air thus introduced into the burner with the pulverizedmaterial is insufficient to produce perfect combustion, an auxiliaryairsupply may be secured through an opening 29', as shown in Fig. 2,leading into the flue 19 and having a regulable damper 30. Theemployment of such an auxiliary air-supply may be desirable in instanceswhere a more perfect pulverization of the material is se-' cured at thepulverizer by reducing the airfeed therethrough below that necessary tosecure perfect combustion of the mixture. In such an instance thepulverizer may be operated to secure the bestcondition of pulverization,while the additional air necessary to obtain perfect combustion will beadded to the fuel through the auxiliary air-supply openin gs 29. Thedeflection of the mixture at the first fire-box from the trunk will becompen: sated at the pulverizer by a recommencement of the adjustablefeed 10 or by increase in such feed, assuming the latter not to havebeen entirely cut off. The succeeding fuel-consuming devices are thenstarted, preferably successively, in the same way, the feed 10 beingproperly regulated to efiect the supply of fuel to be pulverized by thepulverizer. When all the devices are in operation, substantially all thepulverized material will be withdrawn from the trunk or fuel-pipethrough the several branch pipes 17, so that only a minimum quantity ofmaterial will be returned to the pulverizer. If anyone of thefuel-consuming devices requires to be extinguished, the damper 20therefor is closed and the fan stopped. This does not appreciably affectthe supply to the other devices, but results only in the return to thepulverizer of an additional quantity of material and necessitating thecutting down of the feed of material to the pulverizer.

In systems heretofore suggested for feeding pulverized fuel to aplurality of burners the greatest difficulty was found in overcoming thetendency to deliver the bulk of the material at the first take-offs atthe expense of the others and also in maintaining the requiredpercentage of fuel and air throughout the entire travel of the fuel.

By the employ this difficulty is entirelyovercome. As the currents ofair and fuel naturally follow the paths of least resistance, theregulable operation of the auxiliary fans provides for aperfectly-uniform distribution to the several burners.

Having now described my invention, what I claim as new, and desire tosecure by Letters Patent, is as follows:

1. An apparatus for feeding pulverized material to a plurality offuel-consuming devices comprising a pulverizing apparatus, a trunk orfuel pipe extending therefrom, and to which a mixture of pulverized fueland air is supplied, the fuel-pipe being continuous to provide for aconstant circuit of material through the same, a branch leading from thetrunk or fu el-pipe to each fuel-consuming device, and means for cuttingout a portion of the fuel from the trunk and directing it into thebranches, substantially as set forth.

2. An apparatus for feeding pulverized material to a plurality offuel-consuming devices, comprising a pulverizer, a series offuel-consuming devices, a trunk leading from the discharge of thepulverizer adjacent to such devices and returning to the pulverizer,branch pipes leading from the trunk to the fuel-consuming devices, andmeans for cutting out a portion of the fuel from the trunk and directingit into the branches, substantially as set forth.

3. An apparatus for feeding pulverized material to a plurality offuel-consuming devices, comprising a pulverizing apparatus, a

series of fuel-consuming devices, a trunk or fuel-pipe connected withthe discharge from said pulverizing apparatus, said trunk or fuel-pipebeing continuous to provide for a constant circuit of materialtherethrough, a branch leading from the trunk or fuel-pipe to eachfuel-consuming device, said trunk decreasing in cross-section beyondeach branch, and means for cutting out a portion of the fuel from thetrunk and directing it into the branches, substantially as set forth.

4. An apparatus for feeding pulverized material to a plurality of fuel-consuming devices, comprising a pulverizer, a series offuel-consuming devices, a trunk or fuel-pipe leading from the dischargeof the pulverizer and returning to the pulverizer, whereby a continuousflow of material through said trunk or fuel-pipe can be effected, abranch leading from said trunk or fuel-pipe to each fuel-consumingdevice, and means for cutting out a portion of the fuel from the trunkand directing it into the branches, substantially as set forth.

5. An apparatus for feeding pulverized material to a plurality offuel-consu ming devices, comprising a pulverizer employing apulverizing-chamber and a concentric fan-chamber,

. a fuel-pipe leading from the discharge of the fan-chamber andreturning to the inlet thereof, a series of fuel-consuming devices,branches connecting the trunk or fuel-pipe with said devices, and meansfor cutting out a portion of the fuel from the trunk and directing itinto the branches, substantially as set forth.

6. An apparatus for feeding pulverized material to a plurality offuel-consuming devices,

comprising a pulverizing apparatus, a trunk or fuel-pipe leadingtherefrom and to which the pulverulent fuel is supplied, a series offuelconsuming devices, a branch leading from the trunk or fuel-pipe toeach of said devices, and an auxiliary fan in each branch for forcingmaterial therethrough, substantially as set forth.

7. An apparatus for feeding pulverized material to a plurality offuel-consuming devices, comprising a pulverizer, a trunk or fuel-pipeconnected with the discharge of said pulverizer, a series offuel-consuming devices, branches connecting the trunk or flue with saiddevices, and an auxiliary fan in each branch for maintaining acirculation therein, substantially as set forth.

8. An apparatus for feeding pulverized material to a plurality of fuel-consuming devices,

comprising a pulverizing apparatus, a con tinuous trunk or flue leadingfrom the dis; I charge of said pulverizing apparatus so that a constantflow of material through saidfuel 57 pipe can be maintained, a pluralityof fuel consuming devices, a branch leading from the trunk or flue toeach device, and an auxiliary fan in each branch for maintaining av vie?circulation therein, substantially as set forth.

an auxiliary fan in each branch for maintaining acirculation therein,substantially as set forth.

10. An apparatus for feeding pulverized *5 material to a plurality offuel-consuming de Y vices, comprising a pulverizing apparatus, a

trunk or fine supplied with pulverized material therefrom, a pluralityof fuel-consuming devices, a take-off box connected with the trunk orflue adjacent to each device, all'of such take-0E boxes being of thesame size, Q

'95 section beyond each box, a branch leading and the trunk or fluebeing reduced in crossfrom the take-01f boxes to the fuel-consumingdevices, and means for cutting out a portion of the fuel from the trunkand directing'it 1co into the branches, substantially as set forth.

11. An apparatus for feeding pulverized material to a plurality offuel-consuming devices, comprising a pulverizing apparatus,a l j trunkor flue supplied with pulverized material therefrom, a plurality offuel-consuming devices, a take-off box connected with the trunk or flueadjacent to each device, all of, v

such take-01f boxes being of the same size,

and the trunk or flue being reduced in crosssection beyond each box, abranch leading from the take-off boxes to the fuel-consuming devices,and an auxiliary fan in each branch for maintaining a circulationtherein, substa'ntially as set forth.

12. The combination with a trunk or'fuelby air-currents, of a branchconnected therewith, and an auxiliary fan in said branch, substantiallyas set forth.

13. The combination with a trunk orfuel with, an auxiliary fan in saidbranch, anda damper opening into said branch and away from the trunk orfuel-pipe, substantially as set forth.

14. The combination with a trunk or fuel pipe in which pulverizedmaterial is forced by air-currents, of a branch connected there- 7 with,an auxiliary fan in said branch, and means for admitting an additionalair-supply to said branch, substantially as set forth. 7

pipe in which pulverized material isforced: '7

' 12o pipe in which pulverized material is forced' by air-currents, of abranch connected there- 15. The combination with a trunk'or fuel- I Thisspecification signed and witnessed this pipe in which pulverizedmaterial is forced 14th day of June, 1900. by air-currents of a branchconnected therev with, an auxiliary fan in said branch and WILLIAMMAXWELL WIIEILDO). 5 means for admitting an additional andregnl/Vitnesses:

lable air-supply to said branch, substantially FRANK L. DYER,

as set forth. JNo. R. TAYLOR.

